Function of Aquatic Plants

Aquatic plants are a natural part of every lake ecosystem and serve many purposes in a lake. Some plant functions include:
  • The production of leaves and stems that fuel the food web-they are a valuable food source
  • The production of oxygen through photosynthesis-they oxygenate the water via plant processes
  • Providing underwater cover for fish, amphibians, birds, insects and many other organisms
  • Providing a surface for algae and bacteria to adhere to. These organisms break down polluting nutrients and chemicals and are an important source of food for organisms higher in the food chain
  • Emergent plants break wave energy, reducing erosion of the shoreline, while rooted, submersed plants stabilize bottom sediment, reducing turbidity and nutrient cycling that can lead to algae blooms
Necessary Amounts
While it is not desirable to have a nuisance level of plants (especially exotic plants like Eurasian watermilfoil) that prevent the use of the lake by boaters and fishermen, the LMU recommends that aquatic plants be maintained along 30-40% of the surface area of the lake. This means that 30-40% of the lake bottom and water column contain rooted aquatic plants, not that 30-40% of the water surface be covered with plants. Over-treatment of plants with aquatic herbicides is a quick way to create a very murky lake, dominated by algae blooms. Herbicide treatments should be carried out with an understanding of the role plants play in the lake ecosystem.